For many years, packaging engineers have sought to develop an easy to use dispenser for viscous materials like toothpaste. The most common way to package such material is in flexible tubes with thin metallic walls which are squeezed to dispense toothpaste from the tube. Problems, however, arise with such dispensers when substantially all the toothpaste in the tube has been used. The consumer is then faced with either wasting the residual toothpaste by throwing out the tube or struggling to squeeze a portion of that residue onto his toothbrush.
One solution to this problem is to use a compression device to squeeze more of the residual toothpaste from conventional toothpaste tubes. As illustrated by U.S. Pat. No. 3,853,243 to Forman, U.S. Pat. No. 4,019,655 to Moeller, U.S. Pat. No. 4,418,840 to Gardener, U.S. Pat. No. 4,508,240 to Arango, and U.S. Pat. No. 4,515,293 to Hill et al., these compression devices utilize rollers, belts, or fluid pressure to advance toothpaste in the tube toward the tube's discharge opening. Such devices, however, tend to leave toothpaste in the tube, have complicated compression mechanisms, and occupy extra space in the bathroom.
As an alternative to toothpaste tubes, stationary toothpaste dispenser housings have been developed in which toothpaste is discharged from a chamber within the dispenser by means of fluid pressure or a pump. Examples of such toothpaste dispensers are illustrated by U.S. Pat. No. 3,753,516 to Crider, U.S. Pat. No. 3,885,707 to Wittwer, U.S. Pat. No. 4,303,110 to Chen, U.S. Pat. No. 4,424,916 to Pearson, and U.S. Pat. No. 4,508,239 to Rozzen. These dispensing devices, however, are somewhat complex and bulky.
Another alternative to conventional toothpaste tubes is a toothbrush attached to chambers for storing and dispensing toothpaste, as illustrated by U.S. Pat. No. 1,944,067 to Collins, U.S. Pat. No. 3,728,035 to Reitknecht, U.S. Pat. No. 4,145,147 to Schuck, and U.S. Pat. No. 4,457,641 to Smith. These devices also have problems of complexity, weight when filled with toothpaste, and bulk compared with conventional toothbrushes.
Another toothpaste dispenser is disclosed by U.S. Pat. No. 3,563,414 to Coulombe which comprises a container with a spatula attached to a rotatable cover, whereby rotation of the cover causes the toothpaste to be ejected from the container through a discharge opening.
U.S. Pat. No. 3,993,226 to Pavenick discloses a piston-type toothpaste dispenser which travels on a threaded rod to force toothpaste through an outlet. Rotation of the threaded rod is imparted by depression of a longitudinally reciprocating operating means which acts on a kinematic translating means to turn the rod. The structure of this dispenser has many component parts arranged in a complicated manner such that it is expensive to commercialize.
Other piston-type dispensers are disclosed by U.S. Pat. No. 1,716,487 to Davis, U.S. Pat. No. 2,789,737 to Palo, U.S. Pat. No. 3,027,052 to Marraffino, U.S. Pat. No. 3,756,730 to Spatz, U.S. Pat. No. 3,774,816 to Bratton, U.S. Pat. No. 4,139,127 to Gentile, U.S. Pat. No. 4,144,988 to Bergman, U.S. Pat. No. 4,189,065 to Herold, G.B. Pat. No. 221,715 to Watson, G.B. Pat. No. 231,874 to Julliard, G.B. Pat. No. 264,832 to Billeter et al., G.B. Pat. No. 283,644 to White, G.B. Pat. No. 401,003 to Voelk, G.B. Pat. No. 332,300 to Bramson, WO 83/02103 to Morel et al., and G.B. Pat. No. 2,079,379 to Planas.
Another type of toothpaste dispenser which has become especially popular recently is the pump-type toothpaste dispenser.
U.S. Pat. No. 4,437,584 to Connors et al. ("Connors"), U.S. Pat. No. 4,437,591 to von Shuckmann ("von Shuckmann"), and U.S. Pat. No. 4,479,592 to Rusing et al ("Rusing") illustrate one pump-type dispenser model in which toothpaste within a housing is dispensed by advancing a piston on an unthreaded rod within the housing toward a dispensing outlet. In the Connors and von Shuckmann dispensers, the piston is advanced by pushing the rod axially downward and then releasing pressure from the rod which returns to its original position. The piston remains stationary during downward movement of the rod by gripping the dispenser's inner wall. The piston then travels upwardly with the rod when pressure is released. In Rusing's dispenser, the piston is advanced by pushing a cylinder within the dispenser housing downwardly and then releasing pressure on the cylinder. The piston remains stationary during downward movement of the cylinder by gripping the rod and then moves upwardly when pressure is released by gripping the cylinder. The operation of all these devices depends on the gripping of component parts covered with toothpaste. As a result, slippage may occur which either lessens the quantity of toothpaste dispensed by each actuation or precludes the dispensing of any toothpaste at all. Operation of these dispensers is further hampered when toothpaste solidifies adjacent the gripping surfaces of the piston.
Another pump-type toothpaste dispenser is illustrated by G.B. Pat. No. 432,539 to Billing, G.B. Pat. No. 2,049,062 to Wippermann, G.B. Pat. No. 2,064,012 to Lorscheid, and G.B. Pat. No. 2,146,612 to Snedker. These dispensers are all provided with a piston which is mounted on a threaded rod and is advanced within the dispenser. The dispensers of Billing, Lorscheid, Wippermann, and Snedker all require a large number of complicated parts which would tend to make assembly of these dispensers more expensive. As to Snedker, it is also difficult to dispense a relatively constant amount of toothpaste, because dispensing is dependent on the amount of pressure applied to the cap which has a highly variable extent of movement.